茶芽瘿蚊的初步研究

茶芽瘿蚊(Contarinia sp)是我国茶树上新记载的一种害虫,在广东一年发生三代,以幼虫越冬。幼虫期为30～160天;蛹期6～10;成虫寿命平均3.0～4.5天,卵期4～11天。成虫飞翔扩散能力不强,夜间活动,有趋光性,产卵于刚萌动的芽上,孵化后幼虫侵害嫩芽,使芽结成虫瘿。每雌产卵量60～80粒,幼虫终生在芽苞内为害,老熟后落土化蛹。调查了其发生与环境的关系。 防治此虫,采用人工摘除瘿苞和幼虫出苞期及成虫羽化出土盛期在茶篷下施药效果较好,可用药剂DDVP,杀灭菊酯。     

不同日龄的旋毛虫成虫感染小白鼠的实验研究

实验结果显示,每只小鼠由200条3日龄旋毛虫成虫感染的20只小鼠的肠内成虫数值范围6—57条,肌肉内幼虫数值范围17—33条。7日龄成虫感染的20只小鼠的肠内成虫数值范围2—34条,肌肉内幼虫数值范围2—55条。15日龄成虫感染的20只小鼠的肠内成虫数值范围0—8条,肌肉内幼虫数值范围0—3条。30日龄成虫感染的20只小鼠的肠内和肌肉内无成虫和幼虫所见。     

旋毛虫成虫感染小白鼠的实验研究

本文首次采用旋毛虫成虫感染小白鼠。实验结果表明,小白鼠经旋毛虫成虫感染后,在其肠道内发现旋毛虫成虫,在其肌肉内发现旋毛虫成虫。在其肌肉内发现旋毛虫幼虫。肠道内成虫数量范围在2～25条间。肌肉内幼虫主要分布于膈肌、后腿肌和前腿肌。隔肌内幼虫数量范围2～53条,后腿肌内幼虫和前腿幼虫分布较少,后腿肌内幼虫范围在1～7条,前腿肌内幼虫数量范围在2条。我们认为,旋毛虫成虫在某种条件下,在宿主移换过程中可以起感染期作用而感染宿主,引起宿主旋毛虫感染。     

柑桔潜叶蛾(Phyllocnistis citrella Stainton)幼虫期的描述

柑桔潜叶蛾(Phyllocnistis citrella Stainton)属鳞翅目、叶潜蛾科(Phyllocnistidae),以幼虫潜叶为害,是柑桔新梢的主要害虫。 关于该虫的龄期,一直未有报道。仅Ba-Angood(1977),根据隧道和粪便大小判断为四龄,不是经蜕皮壳来鉴别。作者根据蜕皮壳将幼虫分为四龄,蜕皮壳在隧道中可找到。1～3龄取食为害,4龄幼虫停止取食,专司吐丝结茧,建造蛹室。 一龄幼虫头宽0.12毫米,体长0.34～1.03毫米,头胸部显得特别膨大,腹部仅及体长之半,第10腹节不分叉。 二龄幼虫头宽0.20毫米,体长0.77～1.771毫米,体扁平,每节背面的四个凹孔可见,第10腹节己分叉。 三龄幼虫头宽0.34毫米,体长1.5～5.5毫米,体背中线两侧扁平,背中线弧形隆起,尾端尖细,第10腹节分叉的两裂叶延长,后期幼虫具一对较长的尾状物。 四龄幼虫头宽0.32毫米,体长3.23～4.2毫米,体长筒形,口器特化为吐丝器,第8～10腹节逐渐收窄,呈喇叭状。 各龄幼虫的潜道长短及粪便大小,亦可粗略地作为龄期的区分,但以头宽区分较为准确。幼虫头宽的增长(除不取食的四龄幼虫头壳外),成几何级数增加,基本符合戴雅氏定律(Dyar's law)。 幼虫龄期的研究有助于生命表及预测预报和防治的研究。     

绞股兰对果蝇寿命的影响

绞股兰提取物0.5％、1.0％浓度对雄性果蝇平均寿命分别延长11.8％和12.2％。0.25％浓度对雌雄蝇平均寿命分别延长18.5％和24.1％。0.5％绞股兰提取物在孵育期的卵开始给药,其平均寿命比成虫(30日龄)开始给药有明显延长,延长百分率前者为53.3％(♂)、46.1％(♀),后者为14.4％(♂)、9.7％(♀)。绞股兰提取物能促进果蝇幼虫的生长发育,但对果蝇的性活力未见影响。     

昆虫生长调节剂S-31183对淡色库蚊生殖和生活习性影响的实验研究

目的　研究昆虫生长调节剂S 31183在实验室条件下对淡色库蚊成虫吸血和产卵及卵的孵化的影响。方法　在实验室中 ,用S 31183作用于雌、雄成虫后 ,观察其对成虫吸血、产卵和卵孵化的影响。结果　成虫以分子质量数低于 0 1× 10 -9浓度的S 31183饲喂后 ,雌虫产卵率和对照组差异无显著性 ,在浓度达 1× 10 -6时 ,雌虫产卵增加 ,亚致死量的S 31183作用幼虫后 ,发育为成虫的雌虫产卵率下降 ,虫卵孵化率也较对照组降低。结论　高剂量的S 31183影响成虫的产卵和卵的孵化     

旋毛虫肌肉囊包内幼虫数量和囊包形态演化的观察

旋毛虫是一种人兽共患的寄生虫病，我国普遍存在，黑龙江省是重要流行区。旋毛虫成虫寄生于宿主的消化系统，幼虫寄生于肌肉系统，可导致包括人体在内的多种哺乳动物宿主感染旋毛虫病。一般认为，肌肉内囊包幼虫数目1～2条，多则6～7条，肌肉内幼虫囊包沿肌纤维平行走行呈梭形。     

松茸毒蛾发生规律及其防治的初步研究

松茸毒蛾(Dasychira axutha Collenette)是马尾松(Pinus massoniana)的重要害虫,在广东湛江地区一年发生4代,第一代3月中下旬至6月中旬,第二代5月下旬至8月上旬,第三代7月中旬至10月上旬,第四代9月中旬至翌年8月。幼虫一般为6—7龄,以蛹越冬,在枯枝落叶或灌木丛中结茧。 已经采集到18种天敌,包括寄生性天敌11种;捕食性天敌4种。病菌3种。其中特别重要的天敌是松茸毒蛾核多角体病毒。卵期寄生率达51—75％,蛹期死亡率达89％。 试验结果表明,除虫菊脂、敌百虫、敌敌畏和双硫磷对防治幼虫有很好的效果。     

楝科植物对几种害虫的拒食和忌避作用

本文报道了楝科植物(印楝、川楝、苦楝)杀虫剂对几种害虫的拒食、忌避作用室内的测定结果。用叶碟法测定了对三种夜蛾幼虫的拒食作用,结果表明,各种供试样品对斜纹夜蛾3龄幼虫均表现出强烈的拒食活性。5％苦楝种核乙醇提取物对小水稻叶夜蛾5龄幼虫拒食率高达99.8％。2％印楝油对白脉粘虫5龄幼虫拒食率达92％。用枝条选择着落法测定了对柑桔蚜虫的忌避作用,供试的楝科植物样本对桔蚜均表现出强的活性,但对桔二叉蚜则较差。苦楝种核乙醇提取物和印楝油对红脚异丽金龟(虫甲)有拒食作用,但苦楝种核石油醚提取物却表现出明显的引诱取食活性。3％的印楝油对卵圆鳃金龟(虫甲)表现出拒食作用,但1.4％的浓度却刺激此虫大量取食,苦楝种核粉石油醚提取物对此虫又有强的拒食活性。这可进一步说明昆虫对拒食剂表现出复杂的取食和行为反应。     

荔枝爻纹细蜱生物学研究及其在防治上的应用

爻纹细蛾以幼虫钻蛀果实,导致落果。果实接近成熟则仅在种柄蛀食,遗留虫粪于果蒂内,影响荔枝产量和质量。 1982～1984年,在研究其生物学基础上,明确了其幼虫孵化多自卵壳底面直接蛀入果核,取食种腔内的子叶,并且还要在种腔内含物从液态变为固态后才开始入侵,又没有转果习性,这是过去产区喷药多次而保果效果不大的原因。 爻纹细蛾种群数量年中有极为明显的陡升陡降现象,与荔枝品种果实发育密切相关。幼虫取食果核子叶者,蛹大而重,成虫繁殖力强,取食夏秋嫩梢幼叶者,蛹小而轻,成虫繁殖力弱,差异极为显著。 根据荔枝不同品种果实发育进度先后开展预测预报,使用药剂杀虫双混合敌百虫,消灭成虫于产卵前,兼治荔枝蝽蟓,取得显著防治效果。1983、1984两年来虫果率均控制在10％左右,对照为25.6～94％。但1982年没有测报指导,虽多次喷药,虫果率除小核品种外,普遍在80％以上,中山市多宝农场的元技受害率甚至达100％,虫果比为3:1。     

桔芽达瘿蚊生活习性观察

本文详细报告了为害广东柑桔芽鞘新害虫——桔达瘿蚊Dasinerta为害情况、生活史及习性的研究结果,并提出了控制该虫为害的意见。     

Cadmium in tissues of Japanese quail fed oat grain grown on municipal sludge-amended soil

Oats were cultured on soil amended with municipal sewage sludge from Syracuse, N.Y., or on soil alone (control). The oats were fed to male and female Japanese quail through four generations. The extent of absorption of cadmium by the oats and its deposition in tissues and eggs of the first and fourth generations of birds were determined. The tissue levels of cadmium found in the first (F0) generation were kidney greater than liver greater than muscle approximately equal to eggs, with the quail from the sludge-treatment group consistently showing the higher respective tissue levels. Female birds showed consistently higher tissue levels than those of the corresponding males. Kidney and liver tissues and eggs from the fourth generation (F3) quail fed the sludge-treatment diets were also higher than the corresponding controls, but tissues of the male quail were most often higher than the corresponding females.     

早稻三化螟生命表及其分析

本文应用昆虫生命表方法研究三化螟的发生量预测及其致量控制问题,试验在广东省海陵岛进行,当地的主要为害世代为第二世代,根据这个特点,以当代实际卵量与前一世代的顶期卵量的比率,即有效卵量概率,作为连续世代的连接点,组建自越冬幼虫至第二世代的连续生命表,应用排除作用控制指致评价重要因子和分析关健因子的作用,试验结果说明,越冬后幼虫至蛹的死亡,特别是第一世代有效卵量概率对第二世代数量的影响甚大;第一世代幼虫侵入后至第二世代期间,自然种群的发展过程比较稳定,根据第一世代卵量估计第二世代的数量有可能获得较好的顶测结果。     

Increased effects of internal alpha irradiation in Daphnia magna after chronic exposure over three successive generations

A 70-day experiment was performed with Daphnia magna exposed to waterborne Am-241 on a range of concentrations (from 0.4 to 40 Bq ml(-1)) in order to test chronic effects of internal alpha irradiation on respiration, somatic growth and reproduction over three successive generations. Changes in Am-241 concentrations were followed in the water and in daphnid tissues, eggs and cuticles. Corresponding average dose rates of 0.3, 1.5 and 15 mGy h(-1) were estimated. This study confirmed that oxygen consumption increased significantly in the first generation (F0) after 6 days of exposure to a dose rate >or=1.5 mGy h(-1). Consequences were limited to a reduction in body length (5%) and dry mass of females (16%) and eggs (8%) after 23 days of exposure, while mortality and fecundity remained unaffected. New cohorts were started with neonates of broods 1 and 5, to examine potential consequences of the reduced mass of offspring for subsequent exposed generations. Results strongly contrasted with those observed in F0. At the highest dose rate, an early mortality of 38-90% affected juveniles while survivors showed delayed reproduction and reduced fecundity in F1 and F2. At 0.3 and 1.5 mGy h(-1), mortality ranged from 31 to 38% of daphnids depending on dose rate, but was observed only in generation F1 started with neonates of the brood 1. Reproduction was affected through a reduction in the proportion of breeding females, occurring in the first offspring generation at 1.5 mGy h(-1) (to 62% of total daphnids) and in the second generation at 0.3 mGy h(-1) (to 69% of total daphnids). Oxygen consumption remained significantly higher at dose rates >or=0.3 mGy h(-1) than in the control in almost every generation. Body size and mass continued decreasing in relation to dose rate, with a significant reduction in mass ranging from 15% at 0.3 mGy h(-1) to 27% at 15 mGy h(-1) in the second offspring generation.     

Reproduction impairment following paternal genotoxin exposure in brown trout (Salmo trutta) and Arctic charr (Salvelinus alpinus)

This work describes some consequences of paternal germ cell DNA damage on the reproduction success in two fish species. Male brown trout (n = 31) and male Arctic charr (n = 28) were exposed to the model genotoxicant MMS at the end of spermatogenesis to generate a significant DNA damage level in mature spermatozoa (28% and 25% tail DNA in trout and charr sperm, respectively, evaluated through the comet assay). Sperm from each MMS exposed and control fish was then used to fertilize in vitro an aliquot of a single pool of eggs collected from 4 unexposed females for each species. Each batch of fertilized eggs was monitored individually in the hatchery to follow embryonic and larval abnormalities during the fry development. Paternal exposure did not influence fertilization rate or survival rate at hatching in either species. However, MMS paternal treatment resulted in a large array of morphological abnormalities during embryonic and larval development. At the eyed stage, malformations exhibited a 8 fold increase in trout and a 2 fold increase in charr for larvae stemming from MMS treated males as compared with controls. At the end of yolk sac resorption, an increase in the gross morphological abnormality incidence was found in trout larvae originating from MMS exposed males (2.10% vs. 0.93% in control, p < 0.05). When looking more in detail at bony structures after Alizarin red S staining, a 20% incidence of skeletal defects was recorded at the swimming stage. A positive correlation was found between the paternal sperm DNA damage level and the skeletal abnormality incidence of its progeny. During the next 2 months of development, mortality in trout originating from DNA damaged sperm was 3 times higher than in control. After one year, no effect of paternal treatment was found on growth traits (length and weight) but the gross morphological abnormality incidence was still very high in the treated group (27% malformation incidence vs. 0.5% in control). These results demonstrate ecologically relevant consequences of fish spermatozoa DNA damage and stress the value of using this parameter as a biomarker signaling potential long term effects of environmental genotoxins in aquatic systems.     

Histopathological changes in the reproductive system (ovaries and testes) of Oreochromis mossambicus following exposure to DDT

This study assesses the effects of 1,1-bis (4-chlorophenyl)-2,2,2-trichloroethane (DDT) on the reproduction and gonadal histology of adult Mozambique tipalia (Oreochromis mossambicus). The fish were allowed to breed, following exposure to 2 and 5μg/l of waterborne technical-grade DDT for 40 days. Fertilized eggs were artificially incubated. In the 5μg/l exposure, posthatch survival was significantly lower, and prevalence of larval skeletal deformities significantly higher, compared to the control (p<0.05). Incomplete axial development was the common gross deformity in posthatch larvae, caused by failure to develop chondroblasts posterior to the buccopharyngeal cavity. There were no significant differences in the gonadosomatic index of exposed and non-exposed male and female adults. The exposure caused increased oocyte atresia in the ovaries and disorganization of seminiferous lobules in the testes of adults. DDT exposure reduced survival and increased deformities in larvae, at levels that did not cause severe histopathological changes to parental gonads.     

Experimental intoxication by larvae of Perreyia flavipes Konow, 1899 (Hymenoptera: Pergidae) in pigs and some aspects on its biology.

Two pigs were dosed with 5 and 10g/kg bw of fresh Perreyia flavipes larvae collected at the municipality of Pelotas. Two other pigs were dosed with 0.87 and 1.7g/kg of dry P. flavipes (equivalent to 5 and 10g/kg bw of fresh larvae). Another pig was dosed with 0.17g/kg of dry larvae, daily, during 20d. Forty-eight hours after the ingestion, all pigs that ingested single doses showed clinical signs and marked rise in serum aspartate aminotransferase. Alanine aminotransferase and gamma glutamiltransferase were also slightly increased. The pig dosed with 10g/kg of fresh larvae died in 96h. The others recovered in 4-5days after ingestion. No clinical signs were observed in the pigs dosed during 20d with 0.17g/kg of dry larvae. The main lesion observed in the pig dosed whit 10g/kg of fresh larvae was a centrilobular liver necrosis. These results confirmed the toxicity of P. flavipes for swine, demonstrated that the larvae maintain the toxicity after being dried, and suggest no cumulative effect in the larval toxicity. The larvae collected in the field were conditioned in boxes containing swards of native grasses and covered with gauze to prevent the escape of adults on emergence. The larvae pupated from August 11 to September 25. Emergency of adults occurred from February 10 to March 4. Adult females and males live only for 18-36 and 24-48h, respectively. The eggs had an incubation period of 26-33d. The larval period extend from March 1 to August 24.     

Stress response to waterborne Cu during early life stages of carp, Cyprinus carpio.

Following in vitro fertilization, eggs/embryos and larvae of the common carp (Cyprinus carpio) were exposed to 0 (control), 0.3 or 0.8 micromol.l(-1) Cu in artificially prepared fresh water for 168 h. The total amounts of Cu, Na, Ca, adrenocorticotropic hormone (ACTH), alpha-melanocyte-stimulating hormone (alpha-MSH) and cortisol were measured in homogenates of eggs (up to 60 h post fertilization, hpf), isolated embryos (between 60 hpf and hatching) and free-swimming larvae. Only in embryos of eggs exposed to 0.8 micromol.l(-1) Cu a significant accumulation of Cu was observed as well as a concurrent increase in the incidence of spinal cord deformation and larval mortality. Further, when exposed to 0.8 micromol.l(-1) Cu, the whole-body Ca and Na contents were lower at 48 and 72 hpf compared to the controls and those exposed to 0.3 micromol.l(-1) Cu. Conversely, in larvae (>72 hpf) exposed to 0.3 micromol.l(-1) Cu, the Ca content was elevated from 96 hpf onwards. At 48 hpf and onwards, the whole-body ACTH and cortisol contents of the embryos exposed to 0.8 micromol.l(-1) Cu were higher than those in either controls or those exposed to 0.3 micromol.l(-1) Cu. By 96 hpf, ACTH and cortisol contents of the group exposed to 0.3 micromol.l(-1) Cu also surpassed those in controls. The alpha-MSH content in both Cu exposed groups was lower than in controls from 48 hpf onwards. It thus appears that ACTH cells and MSH cells in early life stages of carp exposed to waterborn Cu respond differently; we conclude that in prehatch carp pituitary corticotropes and interrenal cortisol producing cells respond to the chemical stressor Cu and that the resulting hormonal changes provide a sensitive diagnosis for stress as well as toxicity tests.     

Biochemical and physiological sequelae to perinatal exposure to polybrominated biphenyls: a multigeneration study in rats

Polybrominated biphenyls (PBBs) cross the placenta and have been detected in milk. Since biologically stable PBBs are transferred readily from mother to offspring, addition of PBBs to the food supply of one generation may result in exposure of subsequent generations. Therefore, we identified physiological and biochemical sequelae to perinatal exposure to PBBs. Rats were fed diets containing 0, 10, or 100 ppm PBBs from Day 8 of pregnancy until 28 days postpartum at which time all offspring (F₁-10 and F₁-100) were weaned onto control diet, allowed to mature sexually, and bred with littermates to produce the F₂ generation (F₂-10 and F₂-100). F₂-100 littermates were bred to produce F₃-100 animals. Experiments were conducted in offspring from each generation at 28 days of age. Results from this investigation demonstrate that survival can be reduced and growth and development retarded by perinatal exposure to PBBs. PBBs transferred from one generation to the next produced liver enlargement, hepatic histopathologic alterations, hepatic and renal microsomal enzyme stimulation, a reduction in the duration of anesthesia produced by pentobarbital or a large dose of progesterone, and a decrease in the concentration of vitamin A in liver. Therefore, the health hazard associated with exposure to PBBs may not be limited to a single generation.     

Effects of an acute silver challenge on survival, silver distribution and ionoregulation within developing rainbow trout eggs (Oncorhynchus mykiss)

Rainbow trout eggs were acutely challenged with silver (as AgNO(3)) at different stages of development from fertilization through to hatch in moderately hard water (120 mg CaCO(3) l(-1), 0.70 mM (25 mg l(-1)) Cl(-), 1.3 mg l(-1) DOC, 12.3+/-0.1 degrees C) at measured total silver concentrations of 0.11+/-0.004, 1.55+/-0.15, and 14.15+/-1.52 microg l(-1). Four separate acute challenges were conducted, each consisting of 5 days exposure to the respective silver concentration, followed by 4 days recovery after transfer to silver-free water (series 1, 1-10 days post-fertilization; series 2, 8-17 days post-fertilization; series 3, 16-25 days post-fertilization; series 4, 23-32 days post-fertilization). Mortality was not significantly different from control during exposure to 0.11, 1.55, and 14.15 microg l(-1) total silver in series 2, 3 and 4 (mortality for series 1 data could not be calculated for technical reasons). In the four days of recovery following silver exposure, however, there was significant mortality at 14.15 microg l(-1) total silver reaching 100, 31 and 72% in series 2, 3 and 4, respectively, indicating eggs are more sensitive in the period of 8-17 and 23-32 days post-fertilization at this temperature. Mortality following silver exposure was associated with ionoregulatory impairment in series 3 and 4, where up to 60% of whole egg [Na(+)] and [Cl(-)] was lost relative to controls at 14.15 microg l(-1) total silver. Significant but smaller reductions in egg [Na(+)] and/or [Cl(-)] were also observed at 0.11 and 1.55 microg l(-1) total silver. The greatest accumulation of silver in whole eggs and chorions occurred in series 4, reaching concentrations of 0.53 microg g(-1) (eggs) and 15.5 microg g(-1) (chorions) in the 14.15 microg l(-1) treatment. The accumulation of silver in the whole eggs and chorions of the 0.11 microg l(-1) treatment was not different from controls throughout embryonic development. Of the total silver content, only a small proportion of silver was found in the embryos (1-17%), indicating that the chorion is a protective barrier during acute silver exposure.